There is the oft-quoted story of the woman who, after witnessing the family car slip off the jack and pin her husband (or toddler or teenage son depending on who’s telling it), suddenly found the strength to lift the vehicle and save his life. For the average person, that’s about the extent of their knowledge of the human body’s fight or flight response, which is unfortunate. If you study the personal accounts of survival throughout history, you find that the effects of adrenaline in the human body are a little more extensive than “superhuman” strength and reflexes. Instead, what you’ll find is that the side effects of adrenaline sound more like the liability disclaimer seen at the end of every pharmaceutical commercial.

“Consult your doctor before taking adrenaline. Side affects may include…loss of hearing, loss of memory, PTSD, nausea, vomiting, spontaneous defecation, anxiety, bullet time, tunnel vision…”

Yeah. Doesn’t sound so superhuman anymore, does it? If adrenaline were a street drug, it would be the fiend’s last resort.

Nonetheless, it’s important to study the symptoms, because fear isn’t really something you can practice. The kind of danger you have to be in to experience an adrenaline rush, can’t be duplicated in a safe training environment (if you happen to know a way, call the Army. They have a sizable paycheck waiting for you). The best we can do is understand the symptoms, so at least we can recognize them when they occur.

So let’s get down to the finer details of the fight or flight response. For starters, your reaction to a survival situation will be somewhat unpredictable. While most accounts of a traumatic incident have similarities, no two are the same. For starters, many people working in the police, fire, or medical fields have experienced numerous sensory distortions while under stress. These conditions are often grouped together under the same term: Tachypsychia.

This can include severe alterations with one’s perception of time. One of the most common experiences involves seeing the world slow down around you. During a traumatic experience, your brain begins to work in overdrive. It’s processing visual information at a much faster rate, but since the speed of real-time hasn’t changed, it creates the illusion that everything is moving slower. If you weren’t aware that you could experience the world in such a bizarre way, it could add to your stress levels, as happened to this firefighter many years ago when he arrived at the scene of a burning house.

Seeing his fellow fire fighters moving at a snails pace to stop the flames, made him feel even more anxious, frustrated and enraged. Not until he saw a neighbors home video of the incident, did he realize that his perception was wildly different from reality.

Adding to this strangeness, adrenaline may also cause you experience time at a much faster rate, though usually after the danger has passed. Your visual faculties may lose their sense of distance and proportion. Objects that are far away may appear very close and vice versa, and tunnel vision will give you a highly focused perception of a very small area, leaving you blind to your surroundings.

All of these conditions can coalesce to create a pretty bizarre perception of reality. One of the most popular stories involving the effects of Tachypsychia, was taken from the book “On Combat” by Dave Grossman. It involves a shootout between two police officers and a suspect:

“During a violent shoot-out I looked over, drawn to the sudden mayhem, and was puzzled to see beer cans slowly floating through the air past my face. What was even more puzzling was that they had the word Federal printed on the bottom. They turned out to be the shell casings ejected by the officer who was firing next to me.”

Of course, the effects of violent and traumatic incidents aren’t just visual. There’s some pretty puzzling effects on your hearing as well. It turns out that your ears have a protective mechanism when exposed to very loud sounds. Adding to this are the effects of auditory exclusion that are often experienced during stressful situations. Many soldiers and police officers have entered a fray believing their weapons were malfunctioning, only to find that they couldn’t hear the shots. That’s quite an amazing feat to consider, if you’ve ever taken your ear protection off at a gun range.

Traumatic experiences can also wreak havoc on your memory, causing what’s known as critical incident amnesia. The sensory overload that is experienced by the brain, takes a long time to process. Much like a computer, it’s going to take a longer time to download a larger file. It may take you several days before you can fully recall the incident. Or if it was particularly traumatic, your memory of the incident may become repressed, and take many months or years to recover.

As for the more physical effects, an increased pain tolerance is a pretty well known side effect of adrenaline. When you’re in danger, your brain begins producing dopamine, dulling the sensation of pain. Often times people won’t know they’ve been carrying a very severe injury until after the incident has passed.

Other affects include the loss of control of the bowels and urinary tract. This is due to your brain and nervous system dedicating all of its focus on the perceived threat, and ignoring the less important bodily functions. Unfortunately this often results in quite a bit of shame for the person who experiences this, largely as a result of cultural biases. You’ve probably seen it in a lot of war movies. The quaking kid who’s wetting himself before the battle, is a very common movie trope, and is designed to contrast the strong heroes with the weak, inexperienced, and cowards. In reality, losing bowel control is incredibly common, and is a pretty normal response to a life or death situation, regardless of your strength of character.

And finally, after a life threatening situation has passed, most if not all people experience a kind of “burnout”. After only a few minutes of extreme mental and physical intensity, the human body can collapse in exhaustion. All of the biological chemicals that were dumped by the body to help it perform are still circulating throughout, and take a long time to be reabsorbed. The body is desperate to recover from the extreme conditions it was just put through. This is probably the sole reason why, throughout the history of warfare, the “feigned retreat” has been one of the most effective tactics. Once the soldiers think they’ve won, they simply collapse in exhaustion, and are then dealt a devastating blow from fresh enemy troops shortly thereafter.

Overall, adrenaline is not to be taken lightly. It’s not just some superhuman chemical that will let you hulk out on threats to your life. It carries quite a few unpleasant side effects, some of which can be quite nauseating and overwhelming. In the the end though, your body does this for a very good reason. It can be get pretty messy and unpleasant, but it can also save your life one day. Learn the side effects of the flight or fight response now, so that they don’t catch you off guard when your life depends on it.

Additional links:

http://www.beyondintractability.org/bksum/grossman-on-combat
http://www.killology.com/print/print_psychological.htm